How to crash a Windows mobile using MMS

Test code spotlights mobile malware menace

Security researchers have released proof-of-concept code that exploits vulnerabilities in MMS implementations in mobile phones running mobile versions of Windows.

The vulnerability was discovered six months ago by security researcher Collin Mulliner, who published the exploit at the Chaos Communication Congress in Berlin last week in a bid to force manufacturers to deal with the issue.

The flaw involves buffer overflow vulnerabilities in the SMIL (Synchronized Multimedia Integration Language) protocol in MMS messages. As a result long MMS messages appended with malware may crash phones in such a way as to deposit hostile code in the memory of targeted devices. The IPAQ 6315 and i-mate PDA2k are confirmed as vulnerable but other devices running Pocket PC 2003 and Windows Smartphone 2003 are also likely to be at risk of attack using the technique.

Even in devices confirmed as vulnerable the attacker needs to know the correct memory slot where the MMS processing code is executing, so exploitation is far from easy. Malicious MMS message will most likely only crash a device rather than infecting it, reports anti-virus firm F-Secure.

"While [this] is very significant, it does not pose an immediate danger to any large group of users. Although it is possible to create an MMS worm or other malware that uses the vulnerability, this particular exploit cannot be directly used in creating malware," Jarno Niemela, a researcher at F-Secure's Labs, writes. ®